Experimental analysis of an air-to-air heat recovery unit for balanced ventilation systems in residential buildings

Decentralized regenerative mechanical ventilation systems have acquired relevance in recent years for the retrofit of residential buildings. While manufacturers report heat recovery efficiencies over 90%, research has shown that the efficiencies often vary between 60% and 80%. In order to better understand this mismatch, a test facility is designed and constructed for the experimental characterization and validation of regenerative heat exchanger simulation models. A ceramic honeycomb heat exchanger, typical for decentralized regenerative ventilation devices, is measured in this test facility. The experimental data are used to validate two modeling approaches: a one-dimensional model in Modelica and a computational fluid dynamics (CFD) model built in COMSOL Multiphysics®. The results show an overall acceptable thermal performance of both models, the 1D model having a much lower simulation time and, thus, being suitable for integration in building performance simulations. A test case is designed, where the importance of an appropriate thermal and hydraulic modeling of decentralized ventilation systems is investigated. Therefore, the device is integrated into a multizone building simulation case. The results show that including component-based heat recovery and fan modeling leads to 30% higher heat losses due to ventilation and 10% more fan energy consumption than when assuming constant air exchange rates with ideal heat recovery. These findings contribute to a better understanding of the behavior of a growing technology such as decentralized ventilation and confirm the need for further research on these systems.

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Review of Heat Recovery Technologies for Building Applications

Energies ◽

10.3390/en12071285 ◽

2019 ◽

Vol 12 (7) ◽

pp. 1285 ◽

Cited By ~ 6

Author(s):

Qi Xu ◽

Saffa Riffat ◽

Shihao Zhang

Keyword(s):

Heat Recovery ◽

High Performance ◽

Natural Ventilation ◽

Residential Buildings ◽

Global Climate ◽

Real Life ◽

Thermal Conductance ◽

Thermoelectric Module ◽

Residential Building ◽

Ventilation Systems

In recent years, interest in heat recovery systems for building applications has resurged due to concerns about the energy crisis and global climate changes. This review presents current developments in four kinds of heat recovery systems for residential building applications. A extensive investigation into the heat recovery integrated in energy-saving systems of residential buildings is also covered, including passive systems for building components, mechanical/natural ventilation systems, dehumidification systems, and the thermoelectric module (TE) system. Based on this review, key issues have been identified as follows: (1) The combination of heat recovery and energy-efficient systems could be considered as a promising approach to reduce greenhouse gas emissions and make residential buildings meet high performance and comfort requirements. However, real-life evaluation of these systems with economic analysis is insufficient; (2) When heat recovery is applied to mechanical ventilation systems, issues such as pressure leakages and air shortcuts should be addressed; (3) The heat pipe heat recovery system enjoys more potential in being combined with other sustainable technologies such as thermoelectric modules and solar energy systems due to its advantages, which include handy manufacturing and convenient maintenance, a lack of cross contamination, and greater thermal conductance.

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Decentralized Ventilation Systems with Exhaust Air Heat Recovery in the Case of Residential Buildings

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.680.524 ◽

2014 ◽

Vol 680 ◽

pp. 524-528 ◽

Cited By ~ 14

Author(s):

Vera Murgul ◽

Dusan Vuksanovic ◽

Nikolay Vatin ◽

Viktor Pukhkal

Keyword(s):

Heat Recovery ◽

Residential Buildings ◽

Basic System ◽

Ventilation Systems

Decentralized ventilation systems applied in residential buildings are generalized in this article. Basic system elements and devices and tools assigned for its application are considered herein. Basic requirements for design of the ventilation systems used in residential buildings are stipulated.

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Experimental Analysis of CO2 Concentration Changes in an Apartment Using a Residential Heat Recovery Ventilator

Sustainability ◽

10.3390/su131810302 ◽

2021 ◽

Vol 13 (18) ◽

pp. 10302

Author(s):

Kyungjoo Cho ◽

Dongwoo Cho ◽

Taeyeon Kim

Keyword(s):

Flow Rate ◽

Experimental Analysis ◽

Heat Recovery ◽

Co2 Concentration ◽

Infiltration Rate ◽

Ventilation Rate ◽

Living Room ◽

Air Flow Rate ◽

Concentration Changes ◽

Ventilation Systems

Korean law requires at least three levels of control for apartment ventilation systems, including 0.5 air change per hour (ACH). When this law was enacted, it was believed that a 0.5 ACH air flow rate would be sufficient for apartments following building completion. However, ventilation systems cause different air qualities in each space within a unit, depending on infiltration rate and number of occupants. In addition, the current ventilation rate standard is based on an apartment unit’s total area, assuming that all room doors are open. In this study, changes in CO2 concentration were experimentally analyzed based on the number of occupants and various ventilation frequencies with closed doors to analyze air quality differences among rooms in a typical 85 m2 apartment unit in Korea. When the 0.5 ACH ventilation was performed, maintaining 1000 ppm or less was difficult if four people stayed for more than two hours in the living room or two people stayed for more than one hour in the bedroom with closed doors. Our results indicate that it is challenging to maintain a CO2 concentration of 1000 ppm when doors are closed as standards are calculated based on a unit’s total area. Therefore, ventilation systems should be required to provide different air volumes for each room.

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Exergoeconomic analysis of staggered tube cross-flow heat recovery unit incorporated into industrial air-compressor for process water heating

Energy Conversion and Management X ◽

10.1016/j.ecmx.2020.100055 ◽

2020 ◽

Vol 7 ◽

pp. 100055

Author(s):

Richard Opoku ◽

Charles K.K. Sekyere ◽

Solomon Ackumey ◽

Obed Y.W. Abotsi ◽

John P. Kizito

Keyword(s):

Heat Recovery ◽

Cross Flow ◽

Process Water ◽

Water Heating ◽

Air Compressor ◽

Recovery Unit ◽

Flow Heat ◽

Exergoeconomic Analysis

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The Control System for Heating of Small Buildings with Heat Recovery unit and Heat Pump

2020 21st International Scientific Conference on Electric Power Engineering (EPE) ◽

10.1109/epe51172.2020.9269250 ◽

2020 ◽

Author(s):

Jakub Jirinec ◽

David Rot

Keyword(s):

Control System ◽

Heat Pump ◽

Heat Recovery ◽

Recovery Unit

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Proposing Alternative Solutions to Enhance Natural Ventilation Rates in Residential Buildings in the Cfa Climate Zone of Rasht

Sustainability ◽

10.3390/su13020679 ◽

2021 ◽

Vol 13 (2) ◽

pp. 679

Author(s):

Roya Aeinehvand ◽

Amiraslan Darvish ◽

Abdollah Baghaei Daemei ◽

Shima Barati ◽

Asma Jamali ◽

...

Keyword(s):

Natural Ventilation ◽

Residential Buildings ◽

Residential Building ◽

Ventilation Rate ◽

Humid Climate ◽

The Sustainable Development ◽

Passive Strategies ◽

Development Goals ◽

Ventilation Rates ◽

Ventilation Systems

Today, renewable resources and the crucial role of passive strategies in energy efficiency in the building sector toward the sustainable development goals are more indispensable than ever. Natural ventilation has traditionally been considered as one of the most fundamental techniques to decrease energy usage by building dwellers and designers. The main purpose of the present study is to enhance the natural ventilation rates in an existing six-story residential building situated in the humid climate of Rasht during the summertime. On this basis, two types of ventilation systems, the Double-Skin Facade Twin Face System (DSF-TFS) and Single-Sided Wind Tower (SSWT), were simulated through DesignBuilder version 4.5. Then, two types of additional ventilation systems were proposed in order to accelerate the airflow, including four-sided as well as multi-opening wind towers. The wind foldable directions were at about 45 degrees (northwest to southeast). The simulation results show that SSWT could have a better performance than the aforementioned systems by about 38%. Therefore, the multi-opening system was able to enhance the ventilation rate by approximately 10% during the summertime.

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